misc: pci_endpoint_test: Free IRQs before removing the device

In pci_endpoint_test_remove(), freeing the IRQs after removing the device
creates a small race window for IRQs to be received with the test device
memory already released, causing the IRQ handler to access invalid memory,
resulting in an oops.

Free the device IRQs before removing the device to avoid this issue.

Link: https://lore.kernel.org/r/[email protected]
Fixes: e033271 ("pci_endpoint_test: Add 2 ioctl commands")
Signed-off-by: Damien Le Moal <[email protected]>
Signed-off-by: Lorenzo Pieralisi <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>
Cc: [email protected]

Author: damien-lemoal

drivers/misc/pci_endpoint_test.c

@@ -938,6 +938,9 @@ static void pci_endpoint_test_remove(struct pci_dev *pdev)
 	if (id < 0)
 		return;
 
+	pci_endpoint_test_release_irq(test);
+	pci_endpoint_test_free_irq_vectors(test);
+
 	misc_deregister(&test->miscdev);
 	kfree(misc_device->name);
 	kfree(test->name);
@@ -947,9 +950,6 @@ static void pci_endpoint_test_remove(struct pci_dev *pdev)
 			pci_iounmap(pdev, test->bar[bar]);
 	}
 
-	pci_endpoint_test_release_irq(test);
-	pci_endpoint_test_free_irq_vectors(test);
-
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
 }